A large number of telecommunications systems have been, and are being, introduced into the marketplace which provide service to a customer by means of customer-interaction with the system via the customer's telephone. In operation, many such interactive systems provide voice commands and queries to the customer who responds by using a telephone set to generate tones which are detected, identified, and analyzed by the interactive system. As one can readily appreciate, such an interactive system requires its customers to have access to telephones, such as Touchtone.RTM. telephones, which can produce tones. However, there are a large number customers who do not have access to such telephones and, instead, only have access to telephones which generate dial pulses to interact with a telephone network. Such telephones generate dial pulse digits to indicate, for example, the telephone number of a called party. Dial pulse digits are comprised of a train of audible clicks which are separated from one another by periods of silence. For example, in a typical dial pulse digit, each click is approximately 1 msec to 33 msec in length and each period of silence is approximately 6 msec to 33 msec in length. Telephones that generate dial pulse digits cannot generally be used to interact with telecommunications systems that require customers to respond by generating tones.
In light of the above, there is a need in the art for method and apparatus for detecting and identifying dial pulse digits so that, among other reasons, telecommunications systems which utilize such method and apparatus can interact with customers having access to telephone sets which generate dial pulse digits. Further, there is a need for such method and apparatus which can detect and identify dial pulse digits which are contained in a digital or an analog signal which is transmitted, for example, over the public service telephone network ("PSTN").